This invention relates to protective cushioning devices applied to corners and edges of a wide variety of articles including but not limited to kitchen and bathroom cabinets, furniture, case goods, etc. (hereafter collectively referred to as xe2x80x9carticlesxe2x80x9d) which are then customarily packed in cartons, shrink packs or blanket wrapped for shipping.
Shipping containers holding articles such as kitchen cabinets, etc. may be handled numerous times before reaching the end user. Such articles are stacked, stored and transferred by individuals using mechanized equipment such as conveyors, hand trucks and fork lift trucks to name but a few. It is common that a substantial percentage of such articles are bumped, jarred, dropped, squeezed, etc. as they are moved from place to place through the channels of trade. Damage costs can be excessive and it has been found that damage by such handling of products can be substantially reduced by applying corner and/or edge protecting devices to the articles.
Such devices must be low cost but have sufficient cushioning capability, e.g., to protect an article weighing upwards of 250 pounds contained in a shipping container and protected by the protecting devices when dropped from a height of, e.g., 1-3 feet onto a hard surface such as a concrete floor in a warehouse. Such devices must possess adequate resiliency to offer protection from repetitive impacts following an initial jolt.
A type of corner protecting device to which the present invention is directed is illustrated in U.S. Pat. No. 4,838,427. Three triangular shaped sides are joined together at abutted edges to form a hollow pyramid-like shape. The pyramid-like shape is designed to fit the corners of the article and with all the corners of at least one planar surface, e.g., the top, covered by the protective devices, to fit into a shipping container. The devices are constructed of recycled paper fibers, e.g., waste paper and cardboard, that are vacuum formed from a slurry of the fiber. To obtain the desired cushioning effect, the sides of the device are formed into a serpentine configuration that resistively flattens when force is applied. At the side edge junctures of the device which fits over an edge portion of the article adjacent a corner, a channel or tunnel is formed at these junctures to provide a semicircle (cavity) that surrounds the edge and has to be collapsed before the corners of the article are impacted as when dropped on a hard surface.
Whereas the above construction is widely used in industry, there are undesired limits. For example:
(a) An impact directed at an edge can too easily cause splitting of the device at the side edge juncture (the tunnel) with likely damage to the article, i.e., to an underlying edge of the article.
(b) If the article being protected is structured (as it often is) with an open, or inset, top or bottom, the only engagement or support provided by the protecting device is along the edges of the side wall panels that make up that corner. These exposed (or extended) edges of the side wall panels are referred to as xe2x80x9creveals.xe2x80x9d Any impact directed at the edge will in part be directed toward the reveal which is supported by a narrow strip of the side wall of the device overlying the reveal. Because the side wall of the protective device is serpentine in configuration, and because the panel edge thickness is narrow, e.g., typically ranging from xe2x85x9c to xc2xe inch, the edge of the protecting device underlying the reveal is a sequence of spaced apart narrow strips of the support material and likely not adequate to prevent damage.
(c) There is a limit to the thickness of the fiber mat produced in the vacuum forming process and once the serpentine of the device is flattened, the unabsorbed impact force in large measure transmits through the material and is transferred to the protected article.
(d) An impact directed at the peak of the protective device (the apex of the pyramid) will sometimes crush the peak of the device which may cause splitting along the tunnel. The underlying corners and edges are then vulnerable to impacts.
(e) The serpentine shape of the side edges, while enhancing the cushioning capability of the device is extended down to the exposed bottom edge of the device. This exposed edge is susceptible to splitting as the device is pushed onto an article corner under impact which induces spreading of the pyramid sides. Typically, a resistive force to such spreading is provided by a close fitting external shipping container.
In summary, prior art devices were formed into a hollow pyramid shape, the inside walls of the pyramid being a serpentine shape and the juncture between the walls bulged outwardly to form a tunnel, i.e., three tunnels provided for the three side wall junctures which overlay the three edges of an article which converge to form a corner.
The serpentine shapes of these prior devices as viewed from the inside of the pyramid consist of parallel alternating lands and valleys that project from adjacent the exposed bottom edges of the pyramid and intersect with the corner tunnel. One of the valleys of each side wall (at the center of the side wall) intersects at the juncture of the three tunnels, i.e., the peak of the pyramid as illustrated in the accompanying drawings.
As explained in the Background of the Invention, the structure of these prior devices has the problem of (a) splitting apart at the edge tunnels; (b) providing inadequate support for an article corner having a reveal side edge; (c) having inadequate cushion to protect relatively heavy articles when subjected to an impact or when subjected to crushing from heavy loading as when stacked in multiple tiers; (d) impacts directed to the peak of a pyramid resulting in crushing of the peak (and splitting along the tunnel) and (e) splitting lengthwise along the side wall valleys as a result of forces applied during impact that urges spreading of the pyramid sides.
These problems ((a)-(e)) are addressed by the present invention as briefly described below.
(a) The splitting at the tunnels is alleviated by forming the edge tunnels so as to be undulated along its length rather than simply straight. The tunnel undulations provide additional flexure and strength and provides stops against a split that would otherwise run the length of the tunnel. (The undulations reduce in part the spacing from the protected product edge but do not eliminate the spacing.) The flange at the bottom of the tunnel is closed and lessens the likelihood of splits starting at the bottom edge of the tunnel.
(b) The valleys on the inside wall do not extend to the tunnels. Thus, a solid rib (bench or land) of material extends along the side of each tunnel to the peak. A reveal on the protected article which extends a short distance inwardly from the tunnel is thus supported by a continuous strip (land) of the cushioning material.
(c) The serpentine shape formed into the inner walls of the device is produced from a serpentine configured mold form where the spacing across the screen valleys of the serpentine shape is only slightly greater than twice the material thickness (mat thickness). Thus as the material is vacuum formed onto the mold form, the mat thickness projected into the screen valley (on the outside face of the device) from both sides (to produce the lands of the device) is largely merged together to form columns of the material having a double mat thickness which provides added strength in the same manner as a columnar structure. The affect of the double mat thick columns tied together by rebounding arches of single mat thickness is that a two-step cushion is provided. Depending on the severity of an impact, a first force level will collapse the arches which will readily rebound and if a second greater force level is applied, upon collapse of the rebounding arches, that greater force then has to crumple or crush the column which provides superior resistance while nevertheless yielding under such a force level to provide the desired cushioning.
(d) and (e) Resistance to crushing of the peak and splitting of the sides is believed similar to the phenomena of an arch being stronger than a cross beam. The peak is formed into a dome and the exposed bottom or peripheral edge of the pyramid is curled or curved (convexly as viewed from the outer side of the pyramid). Thus, a force applied at the dome or bottom edge that urges splitting is essentially applied against an arch and is more effectively resisted with a lesser likelihood of splitting.
Whereas the above explanations are but brief descriptions of the improved device, the reader will more clearly appreciate and understand the invention and the improvements thereof upon reading the following detailed description of a preferred embodiment and having reference to the accompanying drawings.